Technical design docs are an efficient way to communicate about software architecture and technical solutions. These docs precede an architectural decision record. They benefit from detail, though brevity is an important consideration too.

Feature breakdown documents serve as a single resource to catalogue all information about a feature. As the team enhances the feature, this document becomes a single source of truth about it.

Idea papers allow you to nurture fresh ideas by articulating them clearly. People can use this as a reference to share feedback and enrich the idea. Decision making is also easier if everyone can understand the idea well.

Broadcast how your team will interact with other teams, using a TEAM API.

Distributed projects are chaotic to run without artefacts. The DEEP acronym provides you a mnemonic to remember what to document.

Complex topics need time to understand and to engage with. WUCA outlines a team approach to deal with complex discussions.

A great place to document the static/stable stuff on the project is right in the codebase, in a good, old README file, at the top level of your project folder.